So this is what MS exclusive lineup looks like to me:
March 2018 - Sea of Theives
May 2018 - State of Decay 2
July 2018 - Crackdown 3?
August 2018- Ori 2?
September 2018 Forza Horizon 4?
October/November 2018 Halo 6?
Looks about right except I seriously doubt Halo 6 is releasing this year, If I were to guess they'll probably be doing another spinoff instead, Forza Horizon 4 is almost certainly going to be September and Ori 2 I'm 50/50 on whether it releases this year.